Galvanometer mounting



3 Shee ts-Sheet 1 G. R. GREENSLADE GALVANOMETER MOUNTING INVENTOR Grot/er1? Greenslade G. R. GREENSLADE GALVANOMETR MOUNTING June Al, 1948.

3 Sheets-Sheet 2 Filed Sept. 6, 1944 lNvE-roR June l, 1948. G. R. GREENSLADE 2,442,355

GALVANOMETER MOUNTING Filed Sept. 6, 1944 5 Sheets-Sheet 3 a e L INVENTOR Grot/er1? Geezzsla de mf g M. M

rapplicable to the portable ones. mounting, the galvanometer may be readily held yor clamped ina fixed position in the casing when ithe galvanometer is not in use.

Patented June 1, 1948 GALVAN OMETER MOUNTING Grover R.

Greenslade, Scott Township, Allegheny County, Pa., assignor to Flannery Bolt Company, Bridgeville, Pa., a corporation Ware of Dela- Application September 6, 1944, Serial No. 552,847

7 Claims.

This invention relates to a mounting for precision instruments, especially a precision galvanometer, and provides a mounting for such instrument which is portable, or which is to be used in the neighborhood of vibration producing equipment, and provides an instrument support in which the instrument is unaffected by such local conditions.

In my United States Patent No. 2,326,352, granted August 10, 1943, there is disclosed an electric testing apparatus and method wherein metal parts to be tested are connected into a specially developed bridge circuit and their resistance is measured. By measuring the same part from time to time, an increase in electrical resistance may be indicative of a fracture or incipient fracture. Defective parts may thus be detected and removed before damage has been done. The invention therein disclosed was primarily developed for the purpose of detecting failure of locomotive parts, especially drive pins, before they failed in service, but the invention is of course not restricted to such field of use.

Tests of this character are frequently run in roundhouses, repair shops, sidings, or the like, where mechanical vibration, due to the oper-ation of heavy machinery or movement of railway rolling stock, may disturb the delicate galvanometer to an extent such as to render careful reading of the galvanometer extremely diiiicult.

Moreover, the equipment should be, in many cases at least portable.

The present invention provides a galvanometer support and housing Which may be used in either fixed or portable installations, and is especially With this However, when the galvanometer is to be used, such clamping vmeans may be released and the galvanometer will vbe suspended inside the casing in which it is mounted from a plurality of springs, its only vsupport when so suspended being through the springs, whereby vibration will not be effectively transmitted to it. Additionally, the galvanometer is mounted on a heavy base to which the .springs through which it is suspended are attached. The mass and inertia of the base tend Ato dampen vibrations and slight movements which lotherwise might affect the instrument. Provi- :sion is also made for damping the springs whereby the swaying of the instrument, or the heavy -:base on which it is mounted, is prevented, and vibration in the springs themselves are damped.

My invention may be more fully understood by reference to the accompanying drawings, in which: f f y Figure 1 is a transverse vertical section through the housing and mounting, the instrument itselfY and the base on which it is carried Abeing in elevation;

Figure 2 is a perspective view with the cover of the housing removed;

Figure 3 is a fragmentary vertical section show# ing one of the clamping elements moved down;

Figure 4 is a fragmentary sectional ,view of one of the spring supports in the top of the housing;

Figure 5 is a top plan viewV with the cover removed; and Figure 6 is a perspective View of the assembled case. Y

Referring to the drawings, there is an instrument case designated generally as 2,`with a carrying strap or handle 3 at the top thereof, and a window 4 through which the galvanometermay be viewed. The case is built up over a metal frame comprising a rectangular top 6 formedof angle iron with angle iron corner posts 'I at veach corner thereof. At the bottom of the frame is a sheet metal plate 8 having a flange 9 at each side thereof, Which extends up the side of "the frame.

The casing may be covered with leather or other material resembling somewhatV a piece of luggage.

Resting on the bottom 8, and secured thereto, is a thick block or cushion I0, preferably formed of foam rubber. Y

In each corner of the top of the frame there is welded or otherwise secured, -a vertically "disposed guide member II which has a recess I2 (see Fig. 4) in the top thereof, and in which there is a vertical opening I3. The guide or sleeve II is provided with a downwardly extending extension IIa. Set in the opening I3V is a sleeve member III having a, head I5 and an internally threaded bore I6. A bolt I1 is threaded into the opening I6 and has a head portion I8 at its lowermost end which carries a threaded stud I9. The head I8 is flat against the extension I la so that the bolt I'I may not turn. The head I5 on top of the sleeve Ill is slotted for engagement by a screw driver. By turning the -sleeve I4 in one direction or the other, the bolt I1 which telescopes into it may be raised or lowered.-

As heretofore stated, there is one of these vadjustable fixtures in each corner of the top of the frame. Each stud I9 has the eye portion 20a of a tension spring 20 looped over and a nut on the stud serves to keep the spring from sliding off the stud. Thus there is provided a long tension spring in each corner of the frame and the effective lengths of these springs can be adjusted by the adjustable xture including the telescoping parts above described.

Each of the springs 20 has its lower end engaged over a stud 2| on a heavy metal block 22 positioned within the frame above the cushion I0. On the block 22 is secured the instrument, such as a galvanometer, which mayb'wy known or preferred construction, and which is designated as G, the galvangr'neterheiiig' or less conventionally illustrated.

The tension on the springs 2D is such that the blocks 22 will normally .be lifted ahovethe cushion base I and will hang freely suspended'from the four springs. By adjusting the springs in each corner, the proper conditions of tension and the proper leveling of the galvanometer can be attained. YThe top of the casing is provided with openings through which the screw'slots 'in the heads l are accessible. Qnleafch of the two opposite sides of the frarne @Je metal plates 24. These plates are provided with brackets 25 and 26 to support a transverse shaft 2l that extends across the widtli'of the frarne above'the instrument or galvanorneter. The shaft 21 has a head V28 on one end, this head being prpvidedwitha kerf andV in the Icasingy is an opening 29 so that a screw driver may'beinserted toeng'age the kerf and rotate the shaft A21. The shaft 21 is provided with two beveled gears 3 9. VThese beveled gears engage pinions 3 l on the upper ends ofthe vertical shafts .1?2J 'which shafts are also supported in the brackets lZfalrid 26 respectively, and which have their lower ends positioned in socket bearings 33 on the basel'. by turning thvshaft 2l, both vertical'sc'rew shafts?? may he Simultaneously rotated .Threaded on each shaft 32 is a clamping elernen'tjd which has a sleeve 3:5 through which the-threaded shaft I32npasses, and'whi'ch is interhally threaded to engage the shaft. Each clampingtelernent 13.4 a sponge rubber pad 3,6

on Aits (l.'iiiver-1f`ace.` Eachl of the clamping 'lements tension 31 that rests against the inside of the xnetal iiange. The clamping elements arlpo'sitiondto'loverharig'the heavy metal block 22."

In the operation 0f the clamps, the shaft .21 iatures#.iesimiilianeously .moveihe lamiifrcm position shown in Figure 1 lclownvvardlyto the position shown in Figure 3J The clan'ips ni'oving down hearvagainst the supporting'baseF-22`,`push eeeisifeowe of 'clamped .in the ver# the gal'- vanorneter isnffirmlyheld in the casing and 'can be slafelyfaid conveniently' transported witlit cally described 'as a galvanometer mounting, it is apparent that itmay be used for other precision instruments such as volt or Wattmeters, pyrometers or'the like, and reference to a galvanometer is by Way of illustration of a utility to which the irivhtin IAaSAbeh specifically adl'itd."

'While' I have illustrat'd'and"descrihed a particular' embodiment" of invention, it winbe understood 'that this is 'bSf'Wa'y Of ll'stratina'a that various changes andihodica'tions"'riayhe In'afde Withi the 'ntehiplatiohof 'iny "invention aiiduider'the'scope f th`f'llwing`tlairi`s'."" Ilm.: M l. VA measuring device of the class described, cor'nprising a massive base'block ha'v'i'ng a''rn'a'suriiig instrument thereon, a`fran1"in'fwhich"th`e basf block is'fre to 'move verticallyfspihgs atl tached'to the lolo'ck and' suspendedfron thefrae 35 iwi een@ of Whi'ci the" blecsissvsrildesr D111? rait of olding means in the :frani''niovable into 2'- 'A measuring 'device Qf the @less @@Sgiisd Comprifins 'a' massive :heavy metall has? 16?? having a measuring instrument'tlirecnfa lfljii in which inerafsebiock is tb ,repr verticali and' in i ,hich'the block ,is horina'li .Seifiieii against said pad, and means for simultaneously operating the clamping elements.

5. An instrument mounting and housing comprising a casing, a heavy metal block suspended from tension springs inside the casing and adapted to support a measuring instrument, a pad under said block and normally spaced therefrom, vertically moving clamping elements over the block for releasably pressing and holding the block against said pad, and means accessible from the exterior of the `casing mechanically and operatively connected with said last named means for operating the same.

6. An instrument mounting of the class described comprising a casing, a heavy block within the casing on which an instrument is adapted to be mounted, a plurality of vertically adjustable supports in the top of the casing, tension springs by means of which the block is suspended from the top of the casing, which springs are connected with said adjustable supports and With the block, said adjustable means being accessible for adjustment from the exterior of the casing and comprising screw elements with which the supports are engaged for relative rotation and resilient means supported on the interior walls of said casing and engageable with said springs intermediate their lengths for damping vibrations in the springs and restraining them from swinging between the screw elements and the supports.

'1. An instrument mounting of the class described comprising a casing, a heavy block within the casing on which an instrument is adapted to be mounted, a plurality of vertically adjustable supports in the top of the casing, tension springs by means of which the block is suspended from the top of the casing, which springs are connected with said adjustable supports and with the block, a cushion under said block, a plurality of clamping means movable vertically over the block for depressing the block against the tension of the springs onto the cushion, and means accessible from the exterior of the casing for operating said clamping means in unison.

GROVER R. GREENSLADE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,243,358 Stoddard Oct. 16, 1917 1,364,860 Betts Jan. 11, 1921 1,880,280 Replogle Oct. 4, 1932 2,014,581 Norton Sept. 17, 1935 2,030,349 Bradley Feb. 11, 1936 2,311,396 Judkins Feb. 16. 1943 

